I can give one history on this as my eldest d is 37 weeks pregnant with her second baby. She had terrible spd the 1st time round and was unable to walk for the last 10 weeks of the pregnancy and had to use a wheelchair, but this time, she has it much milder and has reached this late stage still able to walk(not far of course, but still it's even without crutches), it is painful but bearable. She also wondered if running round after number 1 child has made her stronger, or whether ti is coincidence that it isn't as bad. I suspect that it depends, and each person and each pregnancy is different, and there is no way to tell how it will be. The good thing is, like others have said, the SPD vanished after the baby was born, within hours.
She had a c section 1st time and is having another this time. She healed well after the section despite having fragile skin, so we aren't too worried this time. I think the c section versus natural birth question could rage on and on, really there is no fixed answer, but it was the right decision for her, and was for on my 4th child, compared with my 3 natural births it was much easier and I healed much better than the tearing and the bladder damage(to my bladder) caused by the births. I am a bleeder and the section meant that they got at the site of my bleeding much quicker and stopped it so i had far less of a haemorrhage than on the first 3. However for others a natural birth might be the best option, we are all so different....
good luck, Christianne.
Aged 47, dx EDS 3,POTS, Coeliac, breast cancer 2002. I have 4 children: son 14 - HEDS & Coeliac, daughter 25 - HEDS, POTS, pernicious anaemia, daughter 27 - HEDS, Behcets syndrome, also daughter 22 & 3 grandchildren unaffected as yet.